The invention relates to a method of monitoring the crane safety of a crane, wherein the crane has a sensor system and a crane control.
In the more recent past, the demands on the crane safety of a crane during crane operation have been growing all the time, which is partly due to new statutory provisions. Modern lifting apparatus therefore have a crane control for monitoring the crane safety during crane operation. Various sensors provide the crane control with data during the crane work which relate, for example, to the angular position of individual boom elements or to the transmitted forces in the individual components.
The crane control requires the received data for load moment limitation during the crane work to foresee a tilting of the crane or a failure of the supporting structure of the crane and to introduce counter-measures in an emergency. Comprehensive statutory and standard provisions exist for such safety mechanisms.
The load moment limitation is in this respect usually determined in that measured values are detected and forwarded to the control. The control carries out a calculation of the load which is suspended at the crane hook, with the control calculating out the inherent weights contained in the measured value and thereupon determines the load at the hook from the residual remainder of the measured parameter. In this observation, the tolerances of the inherent weights must be observed. With shallow boom positions and small loads at the hook—a situation which occurs, for example on the erecting or setting up of the crane—the impact of these tolerances is out of all proportion.
In contrast to the crane work monitored by the control the setting up of the crane has previously not been subject to any complete monitoring. Setting up is understood as the establishing of the work capability of the crane, such as the assembly of the crane from the transport state into the working state. The setting up procedure is concluded when the crane is in a payload table applicable to the usage.
As described above, the safety demands on the crane operation are intensified regularly to reduce the danger to involved persons as much as possible on the handling of the machines. In the meantime, new provisions have therefore been set up which also require a maximum possible safety status during the setting up procedure of a crane.
If now, however—as required by the new provisions—the setting up process also has to be monitored by the control, the control must already intervene at a very early time although the crane is still by no means at full capacity. It is in particular necessary for the increasingly required setting up case in which long and heavy booms are to be erected to utilize the possible load limits of the crane.